Build in extra time. You know how hard it is getting out the door in the morning with a baby? The same laws of nature apply to trips in the car. You'll have to stop for feedings, diaper changes, and stretching breaks. You'll be much less stressed if you accept that it may take twice as long to get there as it did in your pre-kid days and plan accordingly.
Stop often -- for little and big breaks. Yes, you want to get there, but letting your kids burn off some steam will make the time in the car more bearable. Rivoli suggests finding a local library. "You can read a book, let your child run around, and do a diaper change," she says.
Be aware that 20 minutes after your longish lunch stop, your toddler will need to stop again for a bathroom break.
Book a motel that has an indoor pool. It may cost a little more, but it's something to look forward to, and it will help your child sleep better.